The present invention relates to a device for automatically collecting waste masters used in a stencil printer or similar printer.
It is a common practice with a stencil printer to wrap a master around a print drum, feed ink to the inner periphery of the print drum, and transfer the ink to a paper via the perforations of the master so as to print an image on the paper. After the printing operation, the waste or used master is peeled off the print drum, driven out onto a tray, and then discarded by the operator. This kind of master discharging scheme, however, often causes the ink deposited on the waste master to smear the operator's hands and cloths. To solve this problem, there has been proposed and extensively used a waste master collecting device including a box for automatically collecting the waste master peeled off the print drum and conveyed to the box.
However, if the consecutive waste masters are simply dropped into and stacked on the above box by gravity, they become bulky and cannot be efficiently stored in the box. In light of this, a raising and lowering mechanism using a pantagraph-like arm or an eccentric cam or a pivoting mechanism using an arm and a rotary shaft may be driven by drive means, e.g., gearing or a disk and motor device. The raising and lowering mechanism and pivoting mechaism each causes a compression plate to compress a waste master peeled off the print drum and introduced into the box. These schemes are disclosed in, e.g., Japanese Utility Model Laid-Open Publication No. 61-204765 and Japanese Patent Laid-Open Publication Nos. 59-11281 and 8-142484 as well as in Japanese Patent Application No. 7-161697.
However, the conventional schemes using the compression plate have a problem that the waste master introduced into the box hangs down due to its own weight and cannot reach the deepest portion of the box. As a result, the consecutive waste masters are locally stacked only in the upstream portion of the box with respect to the direction of master transport, obstructing a waste master being introduced into the box.
Technologies relating to the present invention are also taught in Japanese Patent Application Nos. 8-33592 and 8-158415.